Fix stdlib/encodings: expose imported submodules

[albertedwardson]

mypy reports a false positive when accessing encodings.aliases.aliases:

import encodings

def get(key: str) -> str:
    return encodings.aliases.aliases.get(key, key)

reveal_type(encodings.aliases.aliases)

This produces:

main.py:4: error: Returning Any from function declared to return "str"  [no-any-return]
main.py:6: note: Revealed type is "Any"
Found 1 error in 1 file (checked 1 source file)

The revealed type of encodings.aliases.aliases is Any, which causes the dict.get() call to return Any and triggers no-any-return.

At runtime, however, encodings imports certain submodules (including aliases) into its namespace:

Python 3.12.3 (main, Jan 22 2026, 20:57:42) [GCC 13.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
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>>> import encodings
>>> dir(encodings)
['CodecRegistryError', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__path__', '__spec__', '_aliases', '_cache', '_import_tail', '_unknown', 'aliases', 'codecs', 'normalize_encoding', 'search_function', 'sys', 'utf_8']
>>> 

p.s. Actually, utf_8 and utf_8_sig appear at runtime, while only aliases is explicitly imported in __init__.py

[srittau]

Thanks, comment below.

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉